Conventional acoustic transducers, especially those used in hearing aids, strive for wide bandwidth and high efficiency which are also desirable attributes of good microphones. Presently these functions are performed by electrodynamic and magnetic speakers and microphones. Another approach is to use piezoelectric cantilevers to convert from electrical to acoustical energy and vice versa. Electrodynamic and magnetic transducers are very energy inefficient. In battery powered applications such as hearing aids, this represents major power consumption and limits battery life. Piezoelectric microphones have the disadvantage of high mechanical Q, resulting in good sensitivity only in a narrow band at resonance and low sensitivity elsewhere. Most applications for microphones and speakers prefer a wide audio bandwidth with no sharp peaks in the frequency response, hence the piezoelectric transducers are typically inadequate. One method uses a single, flat cantilever of relatively thick layers of silicon nitride and zinc oxide as the transducer. The stresses in the cantilever structure result in a curved diaphragm with wide gaps around the edges. These wide gaps result in poor low frequency performance, making the transducer a poor choice for miniature microphone applications. Another method uses a continuous membrane of high stress and great thickness covered with a thick piezoelectric film. The high stress results in low sensitivity, while the thick membrane (total thickness of several microns) results in a high Q and unacceptable peaks in the frequency response.